Returning to Our Grasslands, Part I of III

With the bark beetle epidemic and the subsequent pinon die-off, we've gone through a number of different perspectives on how to deal with the situation...

  • Topic: Native Plants
  • Author: David Salman and Cindy Bellinger
  • Keywords: trees, bark beetle, habitat, disease, region, Other, grasses
  • Date: April 2004

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“We abuse the land because we regard it as commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect.” Aldo Leopold

With the bark beetle epidemic and the subsequent pinon die-off, we’ve gone through a number of different perspectives on how to deal with the situation. At first we concentrated on spraying. But as the die-off spread from isolated pockets of trees to entire hillsides, large scale spraying is not a good option. It is impractical, expensive, detrimental to bird and beneficial insect populations and will quickly lead to beetle resistance to the pesticides.

Because it was the drought that started weakening the trees, and making them susceptible to the infestation, watering the trees seemed the next logical step. However, because of the huge scale of the die-off, supplemental irrigation is impractical except when done selectively to specimen trees.

In years past and in the early stages of this die-off, it was recommended that infected trees be selectively removed, the wood cut into firewood and covered in clear plastic to “solarize” (kill with heat build-up) the logs, which would kill the larvae to prevent them from hatching into adult beetles and jumping to healthy trees. However, with the massive, wide-scale scope of the problem and the ability of the beetles to fly long distances, this practice is now obsolete.

So with all this information in hand we now ask, “What do we do now?” Options would include:

  • Selective spraying of specimen trees. (Yes.)
  • Selective watering and mulching of specimen trees. (Yes.)
  • Removing dead pinon to form a defensible fire-break around homes and buildings in fire-prone areas. (Yes!)
  • Thinning the dense stands of pinon. (Yes, but it is a gamble. Read on.) By removing the thin, spindly trees and greatly reducing the numbers of trees per acre from hundreds to dozens, the water that does fall from the sky can better support the remaining trees. However, if the drought continues to be as severe as the past few years, and the winter remain abnormally warm, the trees that remain after thinning may succumb anyway.
  • Re-vegetating non-irrigated areas where pinon have been removed with xeric native shrubs, wildflowers and native grasses. (Yes!)
  • Leaving the dead pinon in place and letting them fall to the ground naturally. Until they fall, they will provide habitat for beetle-eating birds and eventually return their biomass to the soil from natural decomposition. (Yes!)
  • Cutting down the dead trees, grinding them into chips and spreading the chips on the landscape to return their biomass to the soil. (Yes, but not as good as leaving them in place.)
  • Cutting down the dead trees and hauling them to the dump. (NO! Very bad idea for all of the reasons above.)
  • Removing and replacing pinons with other tree species. (Yes.)

Finally, the next option is based on the ecology of our area.

Pinon and junipers are actually invaders in our terrain. Before people disrupted the natural competition between trees and grasslands, grass fires periodically swept through the area. The fires killed the smaller trees and seedlings, while renewing and revitalizing the grasslands. The larger trees that survived the fires were widely spaced.

What we’re recommending now is helping our terrain return to the high dry grassland it once was. In the next few issues we’ll talk more about tree removal and discuss re-seeding the terrain with native grasses. The following week we’ll offer suggestions for replacing pinon trees.